Michigan Natural Features Inventory

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Plants and Animals

Vallonia parvulaTrumpet vallonia

Key Characteristics

Identifying features of the trumpet vallonia include a minute (less than .08 inches in diameter), ovate, dull white shell with 3-4 whorls made up of many evenly-spaced raised ribs, a flattened spire and round aperture with no lamellae or folds. The body of the snail is pale yellow in color and small, with short tentacles and stout, rounded eye peduncles.

Natural Community Types

For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.

Management Recommendations

Unchecked recreational rock climbing has been found to negatively effect the lichens and other plants of limestone cliffs, which the trumpet vallonia and wide variety of other land snails rely on (McMillan et al. 2003). Conserving sections of cliff habitat to limit the impacts of recreational activities would benefit many species. Habitat loss, fragmentation and degradation are considered the greatest threats to land snail abundance and diversity (Kay 1995). Increased edge area, forest canopy reductions, and the loss of vegetative ground cover through human disturbance and heavy grazing (Suominen 1999) may alter necessary microhabitat characteristics, such as thick organic litter and moist conditions (Applegarth 1999, Gotmark et al. 2008, Walden 1995, Nekola 2003). Identification and conservation of important habitat areas is an important first step toward management. Fire has significant negative impacts on land snail populations (Applegarth 1999, Nekola 2002). Snag retention may mitigate these effects, as large logs may provide important refuges during fire and drought (Applegarth 1999). Prescribed fire management alternatives should be explored where trumpet vallonia and other vulnerable snails are present. Snails bioaccumulate heavy metals and chemical pollutants (Berger and Dallinger 1993, Regoli et al. 2006) and high exposure has been found to prevent reproduction altogether (Notten et al. 2006). Herbicides and insecticides should be applied with caution and affected populations monitored.

Active Period

Breeding from first week of May to fourth week of June

Survey Methods

As visual detection of this species is difficult, specimens are collected by litter sampling in suitable habitat. Samples are thoroughly heat-dried, soaked in water for a number of hours to separate the various components, and finally passed through a series of sieves. The shells are then able to be hand-picked from the remaining sample material (Nekola 2003).

Litter sampling

Survey Period: From first week of April to first week of October

Time of Day: Daytime

References

Survey References

Nekola, J.C. 2003. Large-scale terrestrial gastropod community composition patterns in the Great Lakes region of North America. Diversity and Distributions 9:55-71.

Suominen, O. 1999. Impact of cervid browsing and grazing on the terrestrial gastropod fauna in the boreal forests of Fennoscandia. Ecography 22:651-58.

Walden, H.W. 1995. Endangered species of land molluscs in Sweden and Madeira. In: The IUCN Species Survivial Commission, The Conservation Biology of Molluscs:19-24 (E. Alison Kay, Ed.) International Union for Conservation of Nature and Natural Resources, Gland, Switzerland.